. >> suarez: and today, continuing her long-running "let's move" campaign, first lady michelle obama-- along with big bird of "sesame street"-- issued new public service announcements encouraging kids to get active and eat healthy. >> no matter what your age, it's important to get your body moving every single day to help keep you healthy. >> look, mrs. obama, i'm getting moving right now by jogging! >> suarez: if a "healthy" trend is developing, it still has a long way to go. as of 2012, the c.d.c. estimated more than one-third of american adults and one out of three of children were obese. we examine today's numbers and the larger challenges obesity still presents with two people who have studied the epidemic closely. michael moss is a pulitzer prize winning writer for the new york times. his new book "salt, sugar, fat. how the food giants hooked us." looks at how companies have contributed to weight gain. and dr. william dietz is the former director of the division of nutrition, physical activity, and obesity at the c.d.c. michael moss, let me start with you. i know there are cavea